Fountain or post-mix beverage dispensing systems are well know and in common use around the world. It is estimated that more than 200,000 outlets in the U.S. alone dispense fountain products.
A fountain beverage dispensing system commonly includes one or more syrup supplies, which typically are concentrate beverage syrups provided in bag-in-box packaging, along with syrup pumps, a carbonator, supply tubing, a chilling system, ratio or flow control devices for beverage components and beverage dispensing nozzles. Sugar based beverage concentrate syrups are typically supplied at a Brix of 50 to 63, the upper limit of which is determined by the viscosity of the syrup. Viscosities of syrups greater than the mid-60's Brix are too high to be handled in conventional fountain beverage dispensing systems due to the high pressure drops incurred by syrup as it flows through the system. High pressure drops result in slow or inadequate syrup flow rates and inadequate pressure at a syrup flow control device to enable the device to function properly and maintain a desired flow rate of the syrup so that, along with a flow control device for diluent, a desired diluent/syrup ratio of the beverage components is delivered to a dispense valve. A typical diluent/syrup ratio for a beverage mixture is on the order of about 5 parts diluent (commonly plain or carbonated water) to 1 part syrup.
Diet or sugar-free syrups are not limited by viscosity. Sugar-free syrup does not increase in viscosity as it is made more highly concentrated, and can be concentrated to the extent that, in theory, a fountain beverage could be reconstituted using a diluent/syrup ratio on the order of 50:1 or more. However, such a high diluent/sugar-free syrup ratio is not used in practice due to the difficulties of controlling the flow rate of syrup to provide a 50:1 ratio, since that would require a flow rate of syrup, relative to diluent, that is so low as to be difficult to control. Existing flow rate controllers have the capability of being adjusted to dispense higher diluent/syrup ratios than 5:1, and most can be adjusted to accurately dispense a diluent/syrup ratio of up to 8:1.
In excess of 500,000,000 gallons of concentrate beverage syrup is dispensed annually in the U.S. As syrup is typically packaged in 5 gallon bag-in-box containers, more than 100,000,000 bag-in-box packages are used annually for syrup. The cost per bag-in-box is presently more than $4.00 when package, manufacturing, and distribution costs are considered.
If fountain beverage dispensing systems were able to handle more concentrated beverage syrups having higher Brix values, so that the diluent/syrup ratio could be greater than 5:1, that would enable more drinks to be provided per bag-in-box package of syrup. That, in turn, would reduce the number of bag-in-box syrup packages used annually. However, as noted above a limiting factor in using more highly concentrated sugar based syrups to increase the diluent/syrup ratio is the inability of flow controllers to accurately control the flow rate of a highly viscous syrup. Also, while sugar-free or diet syrups do not suffer increasing viscosity problems with increases in concentration, there is a practical limit to how highly concentrated a syrup can be and still have its flow rate controlled for obtaining accurate diluent/syrup ratios.
In addition to saving bag-in-box packaging costs, an ability to use more highly concentrate syrups would increase the number of beverages that could be served from a bag-in-box package and reduce the number of bag-in-box changes that are required for service of a given number of drinks.
Another important consideration concerning post-mix beverage dispensing systems is growth of organisms, giving rise to the requirement to sanitize the systems. Currently, the acidity of syrups inhibits the growth of organisms, so the syrup circuits of the systems do not normally require sanitization. However, diluting syrups too much will decrease their acidity level and open the possibility of organism growth in syrup circuits, as is experienced with pre-mix beverage dispensers that are supplied with fully mixed, ready to drink beverages.